I primarily use my Zelda themed New 3DS from around 2017. Occasionally I'll use my original 3DS from around 2012 for visiting my own towns, or games that I have downloaded there. I put in ACNL, and it was stuck on the 3DS logo for the longest time. I reset the 3DS and tried again. Same thing. I then started to wonder if it was because I hadn't downloaded the update for the game, so I tried to do that, but I hadn't downloaded the system update. I go to the settings to download that, and was greeted with a black screen. I reset the 3DS again, and tried the eShop to see if that worked. Black screen. Reset again, and decided to try Super Mario 3D Land which I have downloaded. Surprisingly, it worked. I tried opening ACNL again, and it worked. O__O I'm not sure what happened...